The battery that came in this thing was SMALL, I am putting a group 31 battery in but it wont fit the original tray, plus the original tray while not rusted clean through... wasnt in the best shape. I am using 1/8" angle iron and some sheet metal to build a new tray.
I made my supporting bracket 90 degrees, then realized the core support is not straight up and down so I had to modify it.